FIELD OF THE INVENTION
This invention relates to a high-speed printer of the matrix type wherein a plurality of thin wire styli are selectively impacted in order to deliver an impact to a record medium.
In the present day use of high-speed output devices, such as result from electronic calculators, computing machines, and data processing equipment, it is necessary to print output information very rapidly clearly, efficiently, and often with the capability of producing multiple instantaneous copies.
In such a printer with mechanical elements, the inertia of the mechanical elements is a factor which may limit the speed of operation. In such high-speed use of matrix printers having a plurality of styli wires to form dots which can be printed so as to form character configurations, the low masses of the wire styli and the actuating mechanisms permit the accomplishment of very high-speed operation, especially since each wire stylus need only travel a very short stroke to make its impression on the record medium.
The printer of the present invention is that type which has the styli wires so arranged at its output end so as to form a straight line which can be moved across a record medium rapidly to print and form characters on the record medium. Each character printed would be formed by a sequence of successive wire impacts on the moving medium.
In the prior art, a variety of wire dot matrix printers have been developed having various types of elements and configurations. Some of these printers have a single drive or actuating means which is used to selectively actuate one or more of the wire styli. Other forms of such matrix printers have a plurality of actuating means for activation of various of the wire styli. Among the problems involved therein is the physical space problem wherein the actuating means for each of the various styli require that the styli be widely spaced at the end wherein the styli receive their actuation and at the same time, at the other end, the styli tips (which deliver the impact to the record medium) must be brought into a very small aligned spacial configuration. This has generally required, in the prior art, that each of the styli must be rather sharply bent from a wide separation at one end to a close alignment at the other end with the result that certain styli must be of longer length than others and other styli must be of shorter length than others. The various lengths and various difference in masses involved in the styli and the various amount of arcing or bending along the length of the styli present problems which must be overcome by complex guide means and complex driving or actuation means wherein each stylus must be compensated for the amount of energy impact it receives, the length of the stroke of the activating means which hammers it and the mass and acceleration of the hammer which delivers the impact to the stylus.
Among other problems that arise in the use of the wire styli for printing at high speeds, is the factor of rapid return to "home" position of each stylus without excessive bouncing, vibration, or overshoot. This generally has been accomplished in the prior art by means of spring bias means.
Other factors and problems involved in the prior art in regard to such wire stylus dot printers involve the delivering of sufficient acceleration and velocity to each individual wire stylus in order to result in sufficient impact at the printing end of the stylus to print rapidly and clearly on one or on several underlying recording media, and with sufficient rapidity of return to home position to enable quick availability for the next impact cycle. Thus, the diminution of mass both of the wire stylus and of the actuating or impact means has been a problem of considerable importance in addition to developing rapid yet simple means for selectively actuating each of any of the individual styli both separately and/or simultaneously.